Michael Brown
SAWHORSE
Daikin/Goodman has chosen R32 for their new refrigerant while Carrier has chosen R454b as thier new refrigerant. Both of these are Group A2 refrigerants. Per 2018 IMC 1107.5.1, these refrigerants will require schedule 40 carbon steel liquid lines. Coming from the multi-family side of the industry, I can say that this requirement is being overlooked by everyone. Is there something I am missing here? 1107.5.4 specifies brazed joints for copper tubing carrying A2 refrigerants but that could only be for the suction line. Is there another code section that would allow copper for the liquid lines?